"use strict";
let obj = { name: "后盾人", age: 18, open: true, lesson: [{ title: "js" }, { title: "ts" }] };
// 相当于 let obj:{name:string;age:number;open:boolean;lesson:{title:string}[];}
obj.age = 20;
obj.lesson.push({ title: "css" });
console.log(obj);
